Carp stored in large tubs at Czech Christmas markets align themselves in the north-south direction, suggesting they possess a previously unknown capacity to perceive geomagnetic fields, according to a new study published December 5 in the open access journal PLOS ONE, led Hynek Burda from the University of Life Sciences (Prague), Czech Republic and colleagues from other institutions.
The authors photographed and analyzed the positions of fish in the traditional Czech Christmas market, where carp are stored live in large tubs prior to being sold for the holiday feast. Their study included over 14,000 fish in 25 markets, and the majority of these fish were found to align themselves along the north-south axis. The fish were accustomed to human onlookers, and street lights and other potential disturbances seemed to have no effect on the orientation of the fish. In the absence of other common stimuli for orientation like light, sound or the flow of water, the authors suggest that the fish most likely align themselves to geomagnetic cues.
Citation: Hart V, Kusˇta T, Neˇmec P, Bla´hova´ V, Jezˇek M, et al. (2012) Magnetic Alignment in Carps: Evidence from the Czech Christmas Fish Market. PLoS ONE 7(12):e51100. doi:10.1371/journal.pone.0051100
Financial Disclosure: The study was supported by the Grant Agency of the Czech Republic (Grant 506/11/2121 to HB) and Grant Agency of the Charles University [Grant 116510 to PN]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interest Statement: The authors have declared that no competing interests exist.
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